<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    打印出1000-2000年中所有的闰年，并以每行四个数的形式输出
    <script>
        var count = 0;
        for (var i = 1000; i <= 2000; i++) {
            if ((i % 4 == 0 && i % 100 != 0) || i % 400 == 0) {
                document.write(i);
                count++;
            } else if (i % 1 == 0) {
                document.write("<br>");
            }
        }

        // Symbol.out.print("i");
    </script>
</body>

</html>